Heavy duty transmission architecture

ABSTRACT

A transmission includes a main shaft having two or more main shaft clutches that couple gears to at least one countershaft, and an automated manual transmission coupled to the main shaft via the at least one countershaft. The automated manual transmission includes a front input shaft coupled directly to a main clutch and having a first clutch coupleable to the at least one countershaft, and a rear input shaft coupled to the front input shaft and having a second clutch coupleable to the at least one countershaft. The automated manual transmission is operable to selectively engage the first clutch and the second clutch.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. non-provisionalapplication Ser. No. 14/662,830 filed Mar. 19, 2015 (now U.S. Pat. No.9,989,123), which claims priority to U.S. Provisional Application Ser.No. 61/968,837 filed Mar. 21, 2014, U.S. Provisional Application Ser.No. 61/969,644 filed Mar. 24, 2014, and U.S. Provisional ApplicationSer. No. 61/978,444 filed Apr. 11, 2014, the disclosures of which areincorporated by reference in their entirety. r

TECHNICAL FIELD

The present disclosure relates to heavy duty transmission architecturefor vehicles and more specifically to a transmission architecture thatis configured to better facilitate automated shifting of a slidingclutch transmission, either as an automated manual transmission or adual clutch transmission.

BACKGROUND

Manual transmissions are used for various vehicle applications. Suchtransmissions typically include a multiple speed main section containinga plurality of gears for various range and load gearing configurations.Traditionally, a clutch provides momentary torque interrupt when gearratio changes occur. The clutch is used to engage the transmission froma driving shaft powered by an engine. Shifting with torque interrupt,however, is a manually demanding process that requires repeatedengagement of the driver.

Systems have been developed to improve the shifting process, such asautomated manual transmissions (AMTs) and dual clutch transmissions(DCTs). An AMT includes a clutch, a gearbox, and an embedded dedicatedcontrol system that uses electronic sensors, processors, and actuatorsto actuate gear shifts on the driver's throttle pedal command. An AMTremoves the need for a clutch pedal while the driver is still able tocontrol vehicle movement. The clutch itself is actuated by electronicequipment that can synchronize the timing and the torque required tomake gear shifts quick and smooth.

Dual clutch transmissions (DCTs) have been developed that enableshifting between sets of gears without torque interrupt. In a dualclutch, the inner shaft and the outer shaft may have two or moreconnectable gears (via sliding clutches or sliding clutches andsynchronizers) that drive their respective downstream layshaft membersfor appropriate speed ratios. The clutches can be alternately engaged asthe gear progression is achieved between, for example, four sequentialgears to permit power shifting between the progressive four ratios.

In some transmission designs, the number of gear shift options resultsin the operator having to shift up sequentially through all gear ratiosbefore reaching full speed. Such transmission designs can include eitheran AMT or a DCT. It is desirable to increase the number of gear ratiosin the transmission to facilitate skip shifting in lower gears whilehaving an adequate range of operation of the gears at higher speeds forimproved fuel efficiency. However, in some configurations the layout ofthe transmission can result in an increased length of the input shaftextension from its support bearing, which can compound eccentricityproblems due to the increased length.

Therefore, it is desirable to provide a transmission having an increasednumber of gear ratios available to skip shift in lower speeds and havean adequate range of operation at higher speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, illustrative examples are shown indetail. Although the drawings represent the exemplary illustrationsdescribed herein, the drawings are not necessarily to scale and certainfeatures may be exaggerated to better illustrate and explain aninnovative aspect of an exemplary illustration. Further, the exemplaryillustrations described herein are not intended to be exhaustive orotherwise limiting or restricting to the precise form and configurationshown in the drawings and disclosed in the following detaileddescription. Exemplary illustrations of the present invention aredescribed in detail by referring to the drawings as follows:

FIG. 1 is schematic block diagram of an exemplary transmissionarchitecture configured to provide a plurality of gear ratio changeswith reduced torque interrupt.

FIG. 2 illustrates a 3×3×2 configuration according to one exemplaryembodiment.

FIG. 3 is a schematic representation of an exemplary 3×3×2 configurationwith AMT.

FIG. 4 illustrates exemplary gear ratios for a 3×3×2 configuration insingle and double overdrive arrangements.

FIG. 5 illustrates a schematic of an exemplary 4×2×2 configuration withDCT.

DETAILED DESCRIPTION

FIG. 1 is schematic block diagram 100 of an exemplary transmissionarchitecture configured to provide a plurality of gear ratio changeswith reduced torque interrupt. Various gearboxes can be implemented thatresult in a different number of gear combinations. Also, a clutch 102 isprovided that allows powershifting (i.e., no torque interruption)between gears over at least portions of the total gearbox range ofoperation. Block diagram 100 shows front boxes 104 and back boxes 106that, in combination, result in a total range of gear shifting of the4×2×2 example. Block diagram 100 includes a clutch control 108 thatincludes an electric clutch actuator (ECA) 110, a concentric pneumaticclutch actuation (CPCA) 112, and an optional dual CPCA 114. Shiftcontrol 116 includes a pneumatic actuator 118 and a transmission controlmodule 120, which in one example are combined into a single device 122.Block diagram 100 shows an automated manual transmission (AMT) 124, butincludes a dual clutch transmission (DCT) 126 as an alternative example.

This exemplary transmission architecture can be further configured tohave mechanisms and associated functions of an AMT, so as to providemodel flexibility for application variances. AMT devices may beactivated using electro-pneumatic, electro-hydraulic, andelectro-mechanical devices. An AMT removes the need for a clutch pedalwhile the driver is still able to control vehicle movement.

In a typical AMT control scheme, a constant engine speed is requestedduring engagement so as to equalize engine and clutch torques as well aspossible. Clutch control may provide a clutch torque reference, andthrough a suitable model, the torque reference is converted into aposition reference for the clutch actuator position control. AMT designsprovide model flexibility for application variances. AMT ratio changesteps are designed to be somewhat small and fast, so as to beunnoticeable to the operator whose driving experience is similar to thatassociated with a power shifted device. The transmission can be furtherconfigured to provide even smaller steps when AMT ratio changes areencountered. These very small steps minimize perceived delay or AMTengine droop. The transmission can also be configured to use smallactuation energy/time to accomplish the AMT ratio changes and improvethe operating efficiency in high range (driving speeds) ratios.

Exemplary transmissions can have a direct drive configuration, overdriveconfiguration, or double overdrive configuration. These transmissionscan have a gearbox including a 4×2×2 configuration (16 gearcombinations), a 3×3×2 configuration (18 gear combinations), a 5×2×2 (20gear combinations) configuration or other suitable configurations asdesired. Exemplary single and double overdrive designs are disclosed.Overdrive is commonly known as a gear or gear combination in a motorvehicle that provides a gear ratio that is higher than that of a driveor input shaft, so that engine speed and fuel consumption are reduced.Thus, a single overdrive transmission design includes one gearcombination that is higher than that of the input shaft, and a dualoverdrive transmission includes two gear combinations that are higherthan that of the input shaft.

An advantage of the exemplary transmission architecture is a robustdesign for application variances. In particular, the exemplarytransmission can have a housing configured to contain therein any singlemember of a family of transmissions. Two examples can include the DCTand the AMT. However, the housing can be configured to enclose othersuitable transmissions.

FIG. 2 illustrates a 3×3×2 configuration 200 that is attractive due toits 18 ratios with smaller ratio step size and larger overall ratiocoverage compared to a 12 speed 2×3×2 base. Typically, a 12 speed 2×3×2design includes a two splitter input shaft section. The illustrated3×3×2 configuration 200, on the other hand, includes a three splitterinput shaft section. One challenge with a three splitter input shaftdriven gears is the additional radial displacement of the longer inputshaft with respect to the gearbox centerline. The radial displacement isinherent due to clutch housing, engine flywheel housing, engine block,journal bearing clearance and crankshaft eccentric tolerances. Thesetolerances accumulate to misalign a front pilot journal located atposition 202 of the input shaft (at the engine crankshaft) with respectto a transmission input shaft bearing 204 (affixed to the clutchhousing) and with respect to a gearbox centerline 206. This misalignmentresults in the input shaft rear portion (i.e., the portion residingwithin the gearbox) to be misaligned and radially displaced with respectto the gearbox centerline 206. The radial displacement grows linearlywith respect to the axial distance from the transmission input shaftbearing 204. The means of coupling multiple drive gears to the inputshaft and accommodating the radial displacement with respect to thecenterline presents a challenge.

Therefore, the 3×3×2 configuration 200 includes a front input shaft 208with coupling ability to a coaxial front drive gear 210 or a neutralstate, and a rear input shaft 212 with coupling ability to either acoaxial 2^(nd) drive gear 214 or a coaxial 3^(rd) drive gear 216, oruncoupled in a neutral state. Front input shaft 208 is affixed intorsion to rear input shaft 212 via a spline joint 218. The front inputshaft 208 and rear input shaft 212 are coupled together and axiallycontact each other at a surface 220 to transmit thrust loading. Allthree drive gears 210, 214, 216 are free to rotate about theirrespective input shaft axis when not affixed to an input shaft. Viaspline 218 teeth circumferential clearance between the front input shaft208 and rear input shaft 214, a rear input shaft synchronizer clutch hub222 is able to locate coaxial with either 2^(nd) drive gear 214 or3^(rd) drive gear 216 with little or no radial displacement with respectto those drive gears. Spline 218 teeth are positioned within a bore offront input shaft 208.

FIG. 3 is a schematic representation of a 3×3×2 transmissionconfiguration 300 having a main clutch 302 for operating the threesplitter input that comprises a front input shaft 304 and a rear inputshaft 306. A splitter section 308 is operable via clutch 302, andsplitter section 308 includes a forward clutch 310 and a rearward clutch312. Forward and rearward clutches 310, 312 are coupled together andconfigured to selectively engage a gear 314, a gear 316, or a gear 318via actuators. That is, forward clutch 310 engages gear 316 via a clutchmechanism 320, and rearward clutch 312 selectively engages either gear314 or 318 via rearward or forward motion of rearward clutch 312, andits respective engagement with a clutch mechanism 322 or a clutchmechanism 324.

Configuration 300 includes countershafts 326 having respective gears328, 330, 332 that enable coupling from both input shafts 304, 306,configuration 300 is thereby illustrated as a dual countershaftarrangement. However, although a dual countershaft is illustrated, it iscontemplated that configuration 300 may include only one countershaft326. Clutches 310, 312 are operable to engage, or not, by theirrespective clutch mechanisms 320, 322, 324. As an example, when clutchmechanism 320 is engaged, then clutch 312 is in a neutral position, andinputs shafts 304/306 cause rotation of countershaft 326 via gear 316and gear 328. As another example, when gear mechanism 324 is engaged,then clutch mechanism 320 is disengaged and clutch 310 rotates freelywith respect to gear 316. Input is thereby via gear 318 and gear 330 tocountershaft 326.

Configuration 300 includes a main shaft 334 that is coupled tocountershafts 326 via pairs of gears 332, 336, 338, 340, and is operableas an AMT. Main shaft 334 includes a forward clutch 342 and a rearwardclutch 344 which, through selective forward or rearward motion, engagecountershaft 326 with the main shaft 334. Selective engagement of themain shaft clutches 342, 344 enables implementation of various gearratio combinations, with gear 340 providing a reverse capability. Thus,depending on which gear in splitter section 308 is engaged, and whichgear along main shaft 334 is engaged, various gear ratios may beimplemented. In addition, configuration 300 includes a two speed rangegearbox section 346 that is itself operable via a range clutch 348. Twospeed range gearbox section 346 includes its own range countershafts 350that are engageable via gears 352 or 354. Accordingly, configuration 300may be selectively engaged via controlled activation of three gears inthe splitter section 308, three gears along the main shaft 334, and twogears in the two speed range gearbox section 346—hence the “3×3×2”nomenclature for the disclosed configuration 300.

Thus, at location 358 and also as described with respect to FIG. 2, viaspline teeth circumferential clearance between the front input shaft 304and rear input shaft 306, a rear input shaft synchronizer clutch hub(not shown in FIG. 3) is able to locate coaxial with either drive gear360, 362 without radial displacement with respect to those drive gears.

Accordingly, transmission 300 includes a main shaft 334 having two ormore main shaft clutches 342, 344 that couple gears 332, 336, 338, 340to at least one countershaft 326, splitter section 308 coupled to themain shaft 334 via the at least one countershaft 326. The splittersection includes a front input shaft 304 coupled directly to a mainclutch 302 and having a first clutch 310 coupleable to at least onecountershaft 326, and a rear input shaft 306 coupled to the front inputshaft 304 and having a second clutch 312 coupleable to at least onecountershaft 326. The splitter section 308 is operable to selectivelyengage the first clutch 310 and the second clutch 312, and includesfront input bearing 364 affixed to the clutch housing.

FIG. 4 illustrates exemplary gear ratios 400 for a 3×3×2 configurationin a single overdrive arrangement 402 and a double overdrive arrangement404. Given the 3×3×2 arrangement, each configuration 402, 404 isshiftable through 18 gears 406, 408. Combinations of 18 gearcombinations are selectively achieved via clutches 310, 312 of splittersection 308, clutches 342 and 344 on main shaft 334, and range clutch348. In one example, configuration 402 ranges from an overall gear ratioof 17.322 when in 1^(st) gear, to 0.834 in 18^(th) gear. 17^(th) gearhas a ratio of 1.000 and is achieved when the gears are configured in adirect drive mode. That is, the output rotational speed of thetransmission is the same as the engine speed. Having only one gear witha ratio below 1.000 (18^(th) gear at 0.834), overdrive is achieved forfuel efficiency purposes, and configuration 402 is thereby a singleoverdrive arrangement.

Configuration 404, on the other hand, ranges from an overall gear ratioof 14.431 in 1^(st) gear and has a direct drive arrangement in 16^(th)gear. 17^(th) gear has a ratio of 0.834 and 18^(th) gear has a ratio of0.692. Having two gears with a ratio below 1.00, double overdrive isachieved for fuel efficiency purposes, and configuration 402 is therebya double overdrive arrangement.

Accordingly, configurations 402 and 404 are illustrated in blocks ofthree 410, corresponding to operation of the splitter section through itfirst, second, and third arrangements via respective clutch operation,which repeat as the other gears within the transmission are likewiseshifted up or down through the entire set of 18 gears, and correspond topatterns that may be obtained in a DCT arrangement in which powershifting occurs in repeated patterns. That is, the AMT performs or has a“feel” that is familiar to drivers that are familiar with DCT operationwhen shifting up and down through the total set of gear combinations.Configurations 402, 404 illustrate exemplary percentages 412 thatcorrespond to the ratio step that is obtained through subsequent gearshifts.

Other configurations or arrangements may be achieved in accordance withthis disclosure. For instance, in the above disclosure clutches 342,344, and range clutch 348 are illustrated as synchronized clutches. Thatis, engagement of clutches 342, 344, and 348 occurs by synchronizationwhich occurs during shifting, in one example, in which differentialspeed between rotating components is reduced via a spline and relativespeeds between shafts are thereby controlled. However, clutches 342,344, and 348 may be non-synchronized as well, in which case an inertialbrake (shown as element 356 in FIG. 3, and can be coupled to eithercountershaft and either in the front or the rear) may be employed tocontrol relative speeds before gear engagement. Additionally, FIG. 3illustrates two speed twin countershaft range gearbox section 346operable via range clutch 348, however it is contemplated that aplanetary gear may likewise be employed and engaged via a clutch, as isknown in the industry, as illustrated in FIG. 2.

FIG. 5 illustrates configuration 500 according to another exemplaryembodiment that includes a dual clutch arrangement in lieu of the AMToperation described above. Configuration 500 generally includes asimilar operation as the 3×3×2 arrangement disclosed above, but due tothe presences of the dual clutch, configuration 500 and two clutches inthe transmission section, is instead configured as a 4×2×2 arrangement.

Configuration 500 illustrates a main or dual clutch 502 for operating asplitter input 504 that comprises a front inner input shaft 506 and arear inner input shaft 508. Splitter section 504 is operable via clutch502, and splitter section 504 includes a forward clutch 510 and arearward clutch 512. Forward and rearward clutches 510, 512 areconfigured to selectively engage gears 514, 516, 518, and 528 in a DCToperation.

Configuration 500 includes countershafts having respective gears thatenable coupling from inner shafts 506, 508, and from an outer inputshaft 520. Configuration 500 is illustrated as a dual countershaftarrangement, but may include only one countershaft. Clutches 510, 512are operable to engage, or not, by respective clutch mechanisms. As anexample, when forward clutch 510 is engaged (either fore or aft), thenrearward clutch 512 may be in a neutral position, or selectively engagegears 518, 528 and outer input shaft 520 causes rotation of thecountershaft via either respective gear. As another example, whenrearward clutch 512 is engaged (either fore or aft), then forward clutch510 is disengaged or selectively engage gear 514, 516.

Configuration 500 includes a main shaft 522 that is coupled to thecountershafts via 2 pairs of forward gears and a reverse gear. Mainshaft 522 includes a forward and rearward clutches which, throughselective forward or rearward motion, engage the countershaft with themain shaft 522. Selective engagement of the main shaft clutches enablesimplementation of various gear ratio combinations, with an additionalgear providing a reverse capability. Thus, depending on selective gearengagement, various gear ratios may be implemented. In addition,configuration 500 includes a two speed range gearbox section that isitself operable via a range clutch. The two speed range gearbox sectionincludes its own range countershafts that are engageable via gearsrespective gears therein. Accordingly, configuration 500 may beselectively engaged via controlled activation of four gears in thesplitter section 504, 2 gears along the main shaft 522, and two gears inthe two speed range gearbox section—hence the “4×2×2” nomenclature forthe disclosed configuration 500.

At a location 524 and also as described above with respect to the otherexemplary embodiments, via spline teeth circumferential clearancebetween the front inner input shaft 506 and rear inner input shaft 508,a rear input shaft synchronizer clutch hub (not shown in FIG. 5) is ableto locate coaxial with either drive gear 526, 528 without radialdisplacement with respect to those drive gears.

Accordingly, configuration 500 includes inner input shafts 506/508having a splitter input 504 with two clutches that couple gears to atleast one countershaft, and outer input shaft that couples gears to atleast one countershaft. The gear configurations may be arranged assingle overdrive arrangements, or dual overdrive arrangements, as well,through appropriate operation of the splitter 504

With regard to the processes, systems, methods, heuristics, etc.described herein, it should be understood that, although the steps ofsuch processes, etc. have been described as occurring according to acertain ordered sequence, such processes could be practiced with thedescribed steps performed in an order other than the order describedherein. It further should be understood that certain steps could beperformed simultaneously, that other steps could be added, or thatcertain steps described herein could be omitted. In other words, thedescriptions of processes herein are provided for the purpose ofillustrating certain embodiments, and should in no way be construed soas to limit the claimed invention.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be apparent uponreading the above description. The scope of the invention should bedetermined, not with reference to the above description, but shouldinstead be determined with reference to the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isanticipated and intended that future developments will occur in thetechnologies discussed herein, and that the disclosed systems andmethods will be incorporated into such future embodiments. In sum, itshould be understood that the invention is capable of modification andvariation.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose knowledgeable in the technologies described herein unless anexplicit indication to the contrary in made herein. In particular, useof the singular articles such as “a,” “the,” “said,” etc. should be readto recite one or more of the indicated elements unless a claim recitesan explicit limitation to the contrary.

Reference in the specification to “one example,” “an example,” “oneapproach,” or “an application” means that a particular feature,structure, or characteristic described in connection with the example isincluded in at least one example. The phrase “in one example” in variousplaces in the specification does not necessarily refer to the sameexample each time it appears.

What is claimed is:
 1. A method of manufacturing a transmission,comprising: providing a main shaft having two main shaft clutchesincluding a first main shaft clutch and a second main shaft clutch, thefirst main shaft clutch engageable with a first pair of gears with onein a fore direction and the other in an aft direction, and the secondmain shaft clutch engageable with a second pair of gears with one in thefore direction and the other in the aft direction; and providing anautomated manual transmission using steps that include: a. coupling afront input shaft directly to a main clutch, the front input shafthaving a first clutch coupleable to the two countershafts via a firstsplitter section gear; and b. coupling a rear input shaft directly tothe front input shaft, the rear input shaft having a second clutchcoupleable to the two countershafts via a second splitter section gearand a third splitter section gear; wherein the automated manualtransmission splitter section is operable to selectively engage thefirst clutch and the second clutch; and wherein the gear of the firstpair of gears that is in the fore direction is on the rear input shaft,and the gear of the first pair of gears that is in the aft direction ison the main shaft.
 2. The method of claim 1, further comprisingpositioning a spline joint between the front input shaft and the rearinput shaft, the spline joint having teeth that coaxially locate a drivegear of the second input shaft without radial displacement via a rearinput shaft synchronizer clutch hub.
 3. The method of claim 2, furthercomprising positioning the spline joint within a bore of the first inputshaft.
 4. The method of claim 1, wherein the method of manufacturing thetransmission further comprises: providing the first clutch to becoupleable to the two countershafts via one clutch mechanism; providingthe second clutch to be coupleable to the two countershafts via twoclutch mechanisms; and providing the one clutch mechanism and the twoclutch mechanisms to be selectively engageable via operation of theautomated manual transmission splitter section using the main clutch. 5.The method of claim 4, further comprising coupling a two speed rangegearbox section to the main shaft, the two speed range gearbox sectionoperable via a range clutch.
 6. The method of claim 5, wherein gearselection defined by the first clutch, the second clutch, the two mainshaft clutches, and the range clutch include 18 selectable gear ratios.7. The method of claim 6, wherein the 18 selectable gear ratios includeat least one overdrive gear ratio in which a total ratio of the gears isless than 1.000.
 8. The method of claim 6, wherein at least one of thetwo main shaft clutches and the range clutch is a synchronized clutch.9. The method of claim 6, wherein at least one of the two main shaftclutches and the range clutch is a non-synchronized clutch.
 10. Themethod of claim 9, further comprising coupling an inertial brake to thetwo countershafts.
 11. The method of claim 1, wherein the two main shaftclutches couple at least three gears to the two countershafts.
 12. Themethod of claim 1, wherein the step of coupling the rear input shaftdirectly to the front input shaft further comprises coupling the rearinput shaft to transmit a thrust loading.
 13. A transmission,comprising: a main shaft having two main shaft clutches including afirst main shaft clutch and a second main shaft clutch, the first mainshaft clutch engageable with a first pair of gears with one in a foredirection and the other in an aft direction, and the second main shaftclutch engageable with a second pair of gears with one in the foredirection and the other in the aft direction; and an automated manualtransmission splitter section coupled to the main shaft via the twocountershafts, the automated manual transmission splitter sectioncomprising: a front input shaft coupled directly to a main clutch andhaving a first clutch coupleable to the two countershafts via a firstsplitter section gear; and a rear input shaft coupled to the front inputshaft to transmit a thrust loading, the rear input shaft having a secondclutch coupleable to the two countershafts via a second splitter sectiongear and a third splitter section gear; wherein the automated manualtransmission splitter section is operable to selectively engage thefirst clutch and the second clutch; and wherein the gear of the firstpair of gears that is in the fore direction is on the rear input shaft,and the gear of the first pair of gears that is in the aft direction ison the main shaft.
 14. The transmission of claim 13, wherein the frontinput shaft and the rear input shaft are coupled via a spline jointpositioned between the front input shaft and the rear input shaft, thespline joint having teeth that coaxially locate a drive gear withoutradial displacement via a rear input shaft synchronizer clutch hub. 15.The transmission of claim 14, wherein the spline joint is located withina bore of the first input shaft.
 16. The transmission of claim 13, theautomated manual transmission further comprising: the first clutchcoupleable to the two countershafts via one clutch mechanism; and thesecond clutch coupleable to the two countershafts via two clutchmechanisms; wherein the one clutch mechanism and the two clutchmechanisms are selectively engageable via operation of the automatedmanual transmission splitter section using the main clutch.
 17. Thetransmission of claim 13, further comprising a two speed range gearboxsection operable via a range clutch and coupled to the main shaft, andwherein gear selection defined by the first clutch, the second clutch,the two main shaft clutches, and the range clutch include 18 selectablegear ratios.
 18. The transmission of claim 17, wherein: the 18selectable gear ratios include at least one overdrive gear ratio inwhich a total ratio of the gears is less than 1.000; or at least one ofthe two main shaft clutches and the range clutch is a synchronizedclutch; or at least one of the two main shaft clutches and the rangeclutch is a non-synchronized clutch.
 19. The transmission of claim 18,further comprising an inertial brake coupled to the at least onecountershaft.